Backing a railroad train is a dangerous undertaking. Because the engineer operating the locomotive is often unable to even see the last railway vehicle composing the train, a railroad employee is stationed on the rear vehicle and communicates with the engineer as the train is backed. The last vehicle in each train is equipped with a brake control and an audible warning device. The brake control and audible warning device are both operated by the employee stationed on the last vehicle to warn vehicles and pedestrians of the backing train, as well as, applying the brakes in an emergency.
Railway vehicles are generally equipped with indirect air braking systems. These indirect air braking systems require a positive air pressure within the railway vehicles brake lines to disengage the brakes. The use of indirect braking is beneficial for various reasons. One reason is the brakes may be actuated at various points along a train of railway vehicles, in particular the last railway vehicle, simply by venting air from the brake line.
To accomplish this braking, the railroad industry uses an end of train railroad air hose assembly attached to the end car of a train. The railroad air hose assembly generally includes a coupling, connectable to the brake line of the last railway vehicle; a hose, connected to the coupling; and an exhaust valve in line with the hose in a manner such that positioning the valve in the closed position prevents the escape of air from the brake line and opening the valve allows sufficient air to escape from the brake line to cause the railway vehicle's brakes to engage. The air hose assembly is portable, and is installed on the last railway vehicle as cars are added and removed from the train in the railway switching yard and along the train's route.
Commercially available end of train railroad air hoses include an air driven whistle connected to the hose portion of the railroad air hose adjacent the control arm of the exhaust valve. The air driven whistle is actuated by opening a valve rigidly affixed between the hose portion and the air driven whistle. This allows the person stationed on the last vehicle to provide a warning and eliminates the need for an additional source of power for the warning device.
Although providing an air driven whistle eliminates the need for an additional power source, the whistles are generally not as loud as would be desirable because of the close proximity to which the person operating the whistle is located when the whistle is actuated. It would be desirable, therefore, to have a portable, easily connected, end of train railroad air hose which had an audible warning output sufficient to warn other vehicles and pedestrians at longer distances than the existing air driven whistles.
In addition, persons unfamiliar with the sound of the air driven whistle often do not associate the sound with an audible warning coming from a moving train. It would, therefore, be an additional benefit if the sound generated by the audible warning device was easily associated with a moving train.